This invention relates to a protective coating for an electronic device.
Referring to FIG. 1, a power device 90, for example, may be mounted on a baseplate 92 and attached to a printed circuit board (PCB) 94 (see U.S. Pat. No. 5,526,234, incorporated by reference). Power device 90 has a semiconductor 96 mounted on an electrically nonconductive substrate 98, and conductive pads 100, which are electrically connected to semiconductor 96 by bond wires 102. PCB 94 has a conductive run 108 on the top surface that is connected by a through hole 106 to the bottom surface. Electrical connection between the bottom surface of through hole 106 and a conductive pad 100 is made by solder 110. The amount of solder 110 that contacts conductive pad 100 and the area of solder bond are variable.
An electronic device often needs to be protected from the environment. One method for protecting an electronic device involves covering part of the device with a silicone gel (see U.S. Pat. No. 4,888,226). When the silicone gel is initially applied, it has a viscous constituency which is capable of flowing about the components on the electronic device so as to encase them. The gel is then hardened by curing.